Junkers boiler DIY repair

In detail: Junkers boiler DIY repair from a real master for the site my.housecope.com.

Content

1 Heating systems for country and country houses. Boilers, gas water heaters, water heaters - Repair, service, operation. Recommendations for assembly and installation.
2 How Junkers gas boilers are serviced: repair of the Thermo, Novatherm and Keraklass series, consideration of the causes of breakdowns and the peculiarities of their elimination

In this article we will try to tell you how to make gas boiler repair DIY Junkers ZW 23-1, ZW24-2AE, KE ... These are one of the most common models in the range of Junkers and Bosch boilers.

... First of all, if these boilers break down, you should find the instructions for the Junkers boiler with the model you need. These models of boilers are equipped with a self-diagnosis system and signal that an error has occurred in the operation of the boiler. In models ZW23, ZW23-1, depending on the type of malfunction, the alarm LED and one or more temperature diodes flash.

Junkers boiler malfunction

The German gas technology for individual heating Junkers is renowned for its reliability and workmanship. But, despite this, the company is also developing a network of service centers in order to timely and with a guarantee provide services for the repair and maintenance of boilers, because they, like any other equipment, also need care.

Given the specifics of gas equipment, it is necessary to use the services of professional specialists with the necessary certificates and permits in these matters. In addition, no one knows better than the engineers of branded service centers how to properly repair Junkers gas boilers, their subtleties and features.

Video (click to play).

Even if the installation of the entire heating system based on the Junkers gas heating unit was carried out by professionals, this is not a guarantee of 100% trouble-free operation. Problems can arise due to external factors: low pressure in the gas supply system, in the water supply system, clogged ventilation or poor power supply.

For example, due to untimely cleaning of the boiler ventilation openings, a similar situation may arise, considered on the example of the Junkers Thermo boiler:

In this floor unit, loud pops began to appear when switching burner modes. When the water in the circuit heats up to a certain level, the boiler automation stops the gas supply to the main burner. The flame is maintained only in the igniter. As soon as the temperature in the heating circuit drops to the threshold value, gas is supplied to the main burner again for a new heating cycle. When the main burner is started, detonation occurs due to unburned gas accumulated in the chamber. This is due to insufficient traction. In this model, the air flow into the chamber is organized from below. A special mesh filter is installed at the bottom of the boiler, which eventually becomes clogged with dust and its dense layer ceases to allow air to pass through. Therefore, an abnormal situation arises in the operation of the boiler, for a seemingly insignificant reason. Timely cleaning of this node would have prevented such a situation in advance.

Another common malfunction is contamination of the boiler combustion chamber. Due to the dust that enters the interior of this unit with the air, and possibly also due to the poor quality of natural gas, soot and carbon deposits form inside the combustion chamber, which can clog the nozzles of the gas burner, and also settle in the ventilation system. All this can lead to interruptions in the combustion process, uneven heating of the heat exchanger, incomplete combustion of gas, and as a result, failure of important components, boiler repair or even more sad consequences.

Therefore, in order to avoid the possible costly repair of faulty units, it is necessary to carry out service maintenance in a timely manner.

Another expensive Junkers boiler spare part that can fail is the electronic control board. Like any electronic device, it is sensitive to the quality of the supply voltage, static electricity and temperature conditions. Such boards are practically beyond repair and are quite expensive. Therefore, in order to avoid significant financial expenses, take care of timely cleaning of the boiler, high-quality grounding of its body and do not skimp on a good voltage stabilizer. Some service centers do not provide a guarantee for a boiler that is powered without this device.

If it suddenly happens that you still need repair or replacement of some broken parts, then try to purchase them also in company stores. They will be able to provide you with a branded guarantee and quality for the supplied spare parts for the boilers.

If we talk about the possible repair of the Junkers boiler with our own hands, then you should still think about and weigh the pros and cons. Do not forget the popular wisdom "the miser pays twice." Often, the cause of a breakdown or malfunction is difficult to determine without appropriate experience and diagnostic equipment, and numerous tips on the Internet for self-repairing these units can only suggest an approximate way to solve the problem. After all, a gas boiler is a complex and high-tech device that requires increased attention and qualified maintenance.

Why one article at once about speakers of two different brands Junkers and Bosch? At its core, the Junkers WR-11 and Bosch WR-10 speakers are one and the same speaker. They have slight differences in the body and handles. For example, on Junkers dispensers, you can find a faucet that is attached to a water block and is sold with the column. This is where the differences generally end. Inside the case is the same filling. Both columns are semi-automatic, they have proven themselves well for their simplicity, maintainability, and the price of new products. They have been very popular in Russia for a long time. You can do the repair of these geysers with your own hands, using my step-by-step disassembly instructions.

How does this column work? In order to light it, it is necessary to set the slider on the front panel to the middle position and push it down. Thus, we forcibly open the electromagnetic gas valve and supply gas to the igniter (wick) of the gas column. In order for the gas to ignite, it is necessary to ignite it with a piezoelectric element, which is located in the lower left corner of the gas column. After the spark has ignited the gas coming out of the wick (igniter), you must continue to hold the slider button pressed for 10 to 40 seconds. At this time, the column thermocouple warms up. Then release the slider, while the wick should continue to burn without pressing. If this does not happen, then you must repeat the entire procedure from the beginning. If the igniter does not light up, then, most likely, the column needs repair or maintenance, cleaning the wick (igniter). After the thermocouple has warmed up, it generates an EMF, which independently holds the solenoid gas valve of the column in the open position. The column is ready for use. It remains only to set the gas flow rate you need with the slider and the water flow rate on the water block.

What happens when you open the hot water tap of the mixer? The rest is simple. The membrane of the water block presses on the stem, which in turn opens the mechanical gas valve, and the gas is supplied to the main burner of the Bosch (Junkers) column. The gas mixture ignites from the burning wick of the igniter and heats the water that flows through the radiator of the gas column.

Next, consider the procedure for disassembling Junkers (Junkers) and Bosch (Bosch) gas water heaters for DIY repair, cleaning or maintenance. They are very easy to understand:

1.Remove the handle from the water block, set the gas regulator slider to the middle position, unscrew the two self-tapping screws from the bottom of the column case (there may be just clips on the Junkers) and remove the case.

2. We unscrew the two self-tapping screws securing the cap of the gas exhaust device to the column body and two self-tapping screws on the strip attached to the cap, which fixes the radiator (heat exchanger) of the gas column.

3. Remove the draft sensor 1 (it is located on the right side of the smoke exhaust hood), disconnect the wires from it. We remove the temperature sensor 2 from the heat exchanger by disconnecting the automation wires from it. Here, Junkers and Bosch have slight differences. At Bosch, the wires are removed from the traction sensor, at Junkers they are soldered. Do not try to remove them - you will just break them.

4. Further, nothing prevents us from disconnecting the gas exhaust hood from the heat exchanger (radiator) and the column housing.

5. To remove the heat exchanger, it is necessary to pull out the threaded branch pipe from the left branch pipe of the heat exchanger, having previously removed the latch. You do not have to remove the threaded pipe, but unscrew the hot water hose from it. From the right branch pipe of the heat exchanger, it is necessary to remove the tube that connects the heat exchanger with the water block of the gas column. It is also fastened on a latch, after removing the latter, it can be removed. Rubber rings are used as seals in both connections. They often flow after disassembly-assembly, tk. rubber ages and dries up. Disassemble carefully. When assembling, I advise you to change the rubber bands, in any case, lubricate the pipes during assembly.

6. Nothing prevents us from removing the heat exchanger. Although ... Bosch has two brackets stamped on the back of the case for the heat exchanger. It is better to bend them up. They are not particularly needed and do not affect anything. After that, we remove the gas column heat exchanger up.

7. Disconnect the igniter tube from the burner. From above it is fastened with such a bracket (if it has not been thrown out before you) and in the area of the jet it is fastened in a latch. We pry the tube in the area of the latch with a screwdriver and remove it from the grooves at the top.

8. Behind the igniter tube there is a ceramic ignition electrode. It is also attached to a quick-release latch and is easily removed.

9. In order to remove the burner, we unscrew a pair of self-tapping screws that secure the burner to the gas column housing, and a couple of screws that fix the burner in the gas block of the column. Next, gently press down on the thermocouple with a screwdriver so that it comes out of the burner body. You can stagger the burner upward from the gas block.

10. To clean the burner, take it apart. To do this, we need to unscrew 4 screws. We separate the two parts of the burner from the gas train.

Actually, the disassembly of the column is over. This is sufficient for maintenance (cleaning). The gas block usually does not break if no one has climbed there. There is nothing to do there. This is a factory product. If necessary, you can still remove the water block and disassemble it to replace the diaphragm or stuffing box cover.

We carefully wipe the disassembled elements, rinse them from dust, soot and other deposits.

Special attention to the heat exchanger. I wash it both outside and inside with chemistry or citric acid solution. She, by the way, eats away scale and rust from the inside. If the water from the well is of increased hardness, then this simply needs to be done at each maintenance, because it overgrows from the inside so that you cannot blow it out with a compressor. Scale and soot impair heat transfer, increase gas consumption, and can lead to failure of the heat exchanger. Burned-out heat exchangers on these columns are rare, but clogged with soot are very common. Both the Bosch column and the Junkers begin to heat the water poorly. Usually, all these "shoals" come out at the beginning of winter, when water begins to flow through the pipes colder than in summer.

Dust accumulates in the burner, which enters the apparatus with air, and combustion products are poured onto the openings from above.In this column, the burner cannot be cleaned without disassembling, so chase all those who offer you to vacuum the column, these are freeloaders!

Thoroughly clean the thermocouple from carbon and soot. I have not seen burned-out thermocouples on these columns. It is better to wipe the insulator of the piezoelectric ignition electrode from carbon deposits and dirt with alcohol, so that it is not stitched onto the body. Blow dust out from the ignition tube. Most often, due to this dirt in the tube, the wick becomes weak, smokes, does not heat the thermocouple well, and the column may go out and not ignite. Purging the tube usually solves the problem and the column wick will light up. Ideally, the pilot flame should be blue and strike the thermocouple horizontally. If the flame of the wick is yellow and the large "tongue" goes up, the igniter clearly needs to be cleaned.

As I wrote above, the column is assembled on rubber O-rings. In old columns, they become stiff, and the seals begin to leak. It's good if the master has them. Often you come across different collective farm options from reeling to sealants.
The membrane of the water block, unlike the membranes of Chinese columns, works for a very long time. I saw a torn membrane once. The price of the original membrane is about 1800 rubles, the Chinese counterpart costs around 400 rubles. Who will find how. There is no sense in the original, because the prices are cosmic.
The assembled water block of the gas water heater costs in the region of 4500-5000 rubles. The price is high. Seal repair kits are on sale. You can sort out the water block yourself. Often, the flow regulator leaks at the block. This is treated by replacing the O-ring.
Rarely, but there is a leak in the water block oil seal. Alas, the oil seal cannot be replaced separately. Changeable with water block cover. The price of a cover with a stem is 2700 rubles. Very expensive!
On Junkers, the traction sensor and the overheating sensor are often tormented. Sometimes they torment me so much that I change the whole set of thermocouples and sensors. If it was not part of the plans to change the automation, then the temperature sensor can be painlessly short-circuited (many imported gas water heaters do not have it at all). I do not advise you to short-circuit the thrust sensor a thing that is clearly necessary and saved more than one life. It stops the gas supply to the column if draft is lost in the chimney. It can be short-circuited for a while, so as not to sit without hot water, and only in order to quickly find a replacement for it.

If you decide to buy such a column, then read the reviews on the useful Otzovik website. There, everyone described their column and gave marks. My review is old enough.

Now I would give a solid four to this column. I recommend buying. Usually everything is treated without spare parts. Of the "minuses" of the column, I will note the high price for spare parts. Fortunately, they do not break often.

If anyone is interested, here are the instructions for the Bosch and Junkers gas water heaters

In short, I have everything. Climb into the column yourself, or call me, it's up to you.

Gas water heaters are installed in many apartments and private houses. They allow you to forget about the problems with outages and repairs of the water supply system. On the other hand, they also have disadvantages and are prone to breakage. How to repair Junkers speakers with your own hands? In the article, we have analyzed the main methods.

The Junkers heater is more often subject to malfunctions that relate to ignition systems. Users complain that over time the wick or burner goes out, the device does not ignite, and does not heat the water well.

To determine the cause of the breakdown, you need to inspect the parts, check their performance. We will provide examples of common Junkers problems and how to fix them.

Why is this happening? The reasons may lie in external factors:

Incorrect water connection... Check the condition of pipes and connections. Open the instructions - make sure that the piping is done correctly, water enters the system normally. Otherwise, the pressure in the line will be weak and will not allow the gas valve to open.
No cravings... The latest models are equipped with safety sensors. The principle of the thrust sensor is to detect its presence.If there is no thrust, the sensor sends a signal to the module - the column is turned off. The main reason is the blockage of the chimney. Combustion products are not discharged normally, the burner goes out. The room may have poor ventilation. It is necessary to clean the chimney or install a ventilation valve.

To check the draft, bring a burning match to the control window. The flame deviated - there is a thrust, it burns evenly - no.

A similar situation occurs when the chimney outlet is blocked... Look, maybe there is an object or a satellite dish on the roof interfering with the exhaust of combustion products.
Overheat... Limescale deposits reduce the efficiency of heat dissipation, which can cause the column to overheat. Then the sensor is triggered and it turns off. It is recommended to descale the heat exchanger once a year and install cleaning filters. How to clean a gas water heater, read the previous article.

Sensitive relay... You can observe that the burner ignites, then the igniter goes out. Try to lower the room temperature by opening windows, or replace the relay.
The batteries are empty... Electronic ignition technology is sparked by batteries. If the batteries are discharged, you need to install new ones.

Insufficient water pressure... Experts recommend choosing a column in accordance with the parameters of your system. If the device is too powerful and requires high pressure, you will have to install a pump or install a new one.
Abundance of dust... If you have not cleaned the parts from dust, the flame in the burner can mow and not warm up the thermocouple. Cleaning is carried out with a brush or vacuum cleaner.

What if the technique stopped working? Understand the causes of the problem.

Defective rubber membrane... Why is it needed? When you open the mixer, pressure builds up in the line, which acts on the membrane. Bending, she pushes the stem, and he opens the gas valve. If the membrane is damaged, stretched, the system malfunctions. Replace the element. More details about the repair are written in the article "Water unit of the gas water heater".

Clogged mesh filter... It is located at the entrance to the water unit. Clogged with small debris, pieces of scale, rust. Remove and rinse the part under running water, you can use a brush.
Burner clogging in a gas boiler... During combustion, soot and soot are deposited on the walls. If not removed in time, they will clog the burner holes. Perform cleaning.
Micro switch malfunction... In the normal state, a click is heard during ignition - the switch is activated. If you do not hear sounds, then check and change the element.

Water fittings do not work... It is necessary to clean the parts from rust, lubricate.
Broken wiring... Inspect the entire wiring harness, replace damaged parts.
Broken contacts... Tightening and cleaning of contact groups is being carried out.

Heating systems for country and country houses. Boilers, gas water heaters, water heaters - Repair, service, operation. Recommendations for assembly and installation.

Question: The pressure gauge does not work on my Junkers boiler - what could be? The boiler is new. I replaced the pressure gauge - the result is the same.

Answer: The channel is clogged, the manometer connection point, no water enters the capillary tube.

Question: The Junkers Euroline 23 boiler stopped switching on stably. It turned out that the gas supply valve did not open. The reason is insufficient opening voltage. It was 35-37c, 60c needed. Replacing the electronic board resolved the issue. Is there an electronic circuit for this board? On a new board, 50 kOhm. The rest of the diodes and transistors (without soldering from the board) give the same readings, i.e. can be considered as workers. Could this decreasing resistor affect the voltage drop?

Answer: The resistor can hardly influence, but the coil control transistor can.

Question: a couple of weeks ago, an incomprehensible and unpleasant sound suddenly appeared in the boiler: the impression is that a ratchet works in some kind of "organ" of the boiler. It is impossible to determine by ear. But when you touch the gas valve, you can clearly feel the sound from there. Although it is possible, sound vibrations are transmitted through the boiler fittings. The sound occurs periodically, regardless of whether only the boiler or DHW is working with it. Can anyone have similar problems with such symptoms?

Answer: It is necessary to thoroughly clean the pump, if you are not confident in your abilities, invite a specialist, the part is expensive.

Question: Problem: DHW heating does not work indirectly, heating is in working order! I just stopped heating and that's it!

Answer: Check the DHW flow sensor

Question: Boiler Junkers zs 23-1 ae is a single-circuit boiler with the possibility of heating hot water in a DHW cylinder! The sensor is connected, it does not show an error. Doesn't heat water. When restarting, the yellow indicator blinks twice, the first on the temperature display panel, and the boiler goes into standby mode. When the temperature sensor contact is disconnected, the boiler ignites and immediately goes out. Heating works without interruption. DHW heating was working.

Answer: It is necessary to check the boiler sensor.

Question: Tell me, the water does not pass through the boiler to the hot water supply, where to look?

Answer: If you have a Junkers Euroline, then at the cold water inlet to the boiler.

Question: Help with this question. Junkers Evroline zw 23 did a great job for one season and strange things started happening in this one. After using cold water, closing the tap, the boiler turns on for 5-10 seconds and goes out. The heating circuit works fine. The service technician said it was a hydraulics problem. This begs the question, why did it work normally before and how to fix it?

Answer: Eliminate? Remove water hammer in the cold water pipe at the boiler inlet when it is closed on the mixer - for example, put a check valve.

Question: Boiler Junkers Euroline ZS / ZW 23-1 AE. Stable, once a year, I have a problem with hot water supply. The fact is that when you open the tap to supply hot water, it (water) flows warm, not hot, but at the same time, the batteries get very hot. I call the foreman and he cleans the valve, which, in his opinion, is clogged with tap water. I downloaded the instructions for the boiler, but it does not say anything about the procedure for cleaning the valve, so I ask for your advice. To clean the valve, it is necessary to completely dismantle the entire assembly, or can this be done without removing it? Maybe there is at least a brief description of such a procedure?

Answer: The 3-way valve can be removed quite easily, after draining the heating water from the boiler, try replacing it if you are tired of repairing it.

Question: There was a problem with the Junkers ZW-23-1 KE 23 boiler worked fine, and this winter it all started. At first, the boiler could not turn on normally, turn on and off + turn on and off + turn on and off and so for 20-30 minutes it could do as if it did not have enough gas to ignite. DHW was working fine at this point. The serviceman can offer nothing but cleaning the boiler, but I say to him, in my opinion, the matter is in the gas part, the boiler is serviced 2 times a year. And yesterday the column started to drive - it turns on there is a frantic noise of gas and after 5 seconds it turns off and cannot turn on normally. It will take some time, then it will work. Tell me where to start?

Answer: clean or replace the ionization electrode. Perhaps the problem is in the board, the board does not see the minimum flame, check the capacitor C4 in the boiler.

Question: The Junkers Evroline zw 23 ke boiler heating is working normally, when the hot water tap is opened, there is a strong (noisy) gas combustion - then the burner turns off-on again. etc. With a slow opening, it seems in the mode, but if you open the tap somewhere else, everything repeats. The heat exchanger has just been cleaned.

Answer: Check the gas valve settings according to the instructions.

Question: I have a Junkers boiler zw 23 ke 12. There is a problem for a month now.I turn on hot water, the boiler starts to make noise and a sound begins in the pipes, as if they are being hit with a hammer and the water does not heat up. The fault reset key flashes about once every 4 seconds, but the temperature shows either 90 or 45. What could be the problem?

Answer: If the pressure in the boiler is correct and the pump has not jammed, the heat exchangers will definitely be flushed. Also check the air vent and volume compensator.

Question: Junkers Euroline ZW23KE boiler (installed 10 years ago). After a thunderstorm, flashes red and green 75. What could be? The board refused?

Answer: See flame control circuit.

Question: Boiler Junkers Euroline 23-1. Turbine. An error of the following form: The fault reset button is flashing, and the diodes are at 45 and 90 degrees. According to the instructions - the pressure sensor does not work. If I understand correctly the pressure sensor is it the same pressure switch? I tried to reset the error through CUT, but the result is the same. I removed the case, blew the venturi tube, blew it into the pressure switch too, maybe the contacts somehow got stuck, they jiggled normally. Then, through the reset button, he removed the error and the boiler started up. But after half an hour, the picture is again the same. Tell me what it can be and how to check it. Maybe for resistance or whatever. (there is a multimeter). Or is it a matter of the board. Or buy a new pressure switch?

Answer: 1 - check the moment of the accident - if the turbine is working, 2 - if it works, then check the voltage on the pressure switch with a tester.

Question: The pressure sensor stopped responding, unscrewed it, blew it out with water pressure - it works, put it back in place, filled it with water does not show. I unscrewed the sensor, when the system is filled with water, there is no water in the place where the sensor is connected, I fill it, the bypass is activated, and there is no water at the junction of the sensor, I unscrewed the plug located below, blew everything clean. What needs to be done for water to flow into the sensor?

Question: Such a problem - the Junkers Euroline zw-23 KE 2321 DHW boiler works normally, after turning on the boiler for heating it works for an hour or half an hour and turns off, after 3-4 hours it turns on itself and again the same story. Once, when I opened the tap for adding cold water to the system, the boiler began to work, after turning off the tap it immediately turned off. please tell me what could be the reason.

Answer: you need to check everything, I would start with an NTC sensor.

Question: I have a Junkers Euroline boiler. In operation, it worked fine for 5 years, but recently it has become poorly started on heating, there is an arson, a gas flash and immediately goes out, then after 10-12 seconds everything repeats and so on 6-10 times until it starts. The impression is that the gas valve does not open. Tell me what you need to do to fix this?

Answer: Clean the ionization electrode and possibly repair the board.

Question: Tell me who has come across this: when hot water is started, the boiler lights up, but after 1-10 minutes it turns off and the first light blinks. Then the boiler can be started only after disconnecting the power supply for a couple of minutes. What could it be??

Answer: NTC flow line or pump.

Question: There is a Junkers Euroline ZW-23-1-AE turbocharged boiler. The turbine is working very loudly. When inspecting the turbine, I found a fairly large anchor play (1.5-2mm). The inner bearing rotates with a slight extraneous sound, but the loud sound comes from the backlash. The reason for the appearance of backlash, I thought, was the shift of the inner bearing along the axis of the armature. But it is fitted very tightly, and slight (so as not to damage the bearing) attempts to move it along the axis did not lead to anything.

1. In general, is it possible to change the inner bearing of a turbine or is it not practiced by anyone?
2. In the case of replacing the turbine, can you put in a less powerful one so that it does not buzz so much? I have a 50W turbine, maybe there are 25-30 watt turbines. The heated area is about 60m, the boiler always operates at minimum output.

Answer: The backlash is not from the sound of the turbine! If you can - Change the bearing.

Question: Turbocharged boiler Junkers Euroline.Heating works out decently, but the hot water supply is playing pranks. In the draw-off mode, it heats both hot water and heating. Replaced the 3-way valve insert with a new one. The drive operates DHW heating. I washed the secondary heat exchanger on the heating side - there was debris, but not critical. I removed the 3-way drive, pressed the stem all the way down - the result is the same, both hot water supply and heating are working. Give advice.

Answer: Incorrectly assembled three-way valve, debris.

Question: Good day, everyone. I have a Junkers Evroline ZW23KE boiler installed. Now the following problem has appeared: on heating, the burner works in medium mode, and with hot water supply (the temperature regulator is in a position higher than average), the maximum flame immediately turns on, the heat exchanger starts to make noise like a kettle before boiling. The temperature on the indicators reaches 90 and the gas supply is turned off. The temperature was lowered by the flow of water - the gas turns on and everything starts from the beginning. If the DHW regulator is in a position less than average, the maximum flame is turned on, then the flame decreases to medium and then it works with a constant flame change (then an increase, then a decrease). I suspect it's time to clean the plate heat exchanger. For 8 years of operation, I have never cleaned it. But since not completely sure of my conclusions, so I decided to consult with you. Have I identified the problem correctly?

Answer: And the primary heat exchanger also needs to be cleaned.

Question: Junkers Euroline. The pressure switch does not work. Pull with your mouth - it works. The turbine is spinning, but there are no discharges on the tubes. The exhaust pipe is in order. Not crammed anywhere. Has the turbine started to blow weakly?

Answer: Replace or blow out the venturi, adjust the pressure switch.

How Junkers gas boilers are serviced: repair of the Thermo, Novatherm and Keraklass series, consideration of the causes of breakdowns and the peculiarities of their elimination

Despite the fact that Junkers carefully monitors the quality of its products, gas boilers of their production can also fail over time. It is preferable to repair malfunctions in such heating devices with the hands of specialists. However, if you take into account the causes and nature of the breakdown, you can fix the boiler operation yourself.

Boiler device Junkers ZW

The reasons that can disable Junkers gas boilers can be explained by external factors:

intermittent power supply;
low gas pressure in the system;
clogged ventilation;
in poor water quality in the tap.

A troubleshooting technology is selected based on the severity and possible damage to the entire unit. This can be as a cosmetic repair associated with the coating of water and gas pressure pipes with paint or anti-corrosion compounds, preventive, associated with routine cleaning or replacement of some component parts, as well as major troubleshooting measures that may be caused by a violation during installation or in the process. exploitation.

Among the elements that are most susceptible to failure under the influence of external factors, one can single out:

gas burner;
electronic board;
circulation pump.

Repair or cleaning of the burner is necessary if the following malfunctions occur:

lack of spark;
the spark goes in the wrong place;
the spark passes, but the flame does not ignite;
the flame goes out after releasing the ignition button;
the water temperature does not correspond to the set one;
there is noise during the operation of the burner (hissing, loud popping).

In this case, the causes of violations may be the presence of air or moisture in the diesel filling, a violation of the pumping pressure, a malfunction of the shutter valve, as well as untimely cleaning of the ventilation holes (chimneys or mesh filters).

Burner device in the Junkers Mora boiler

For example, floor-standing gas boilers Junkers of the Thermo series are distinguished by the fact that the air flow into the combustion chamber is organized from below. Also at the bottom of the chamber there is a filtration mesh.Over time, dust collects on it and, as a result, a dense layer of small particles does not allow air to pass to the firebox or, on the contrary, accumulates in the chamber. Because of this, when the boiler is turned on from the main burner, air detonation can occur, and, as a result, a loud pop. As a result, the flame will be maintained only in the igniter and therefore the water heating temperature may differ from the one set in the settings. Repair, in this case, is very easy to carry out, simply by removing dust from the filter.

All Junkers floor-standing and wall-mounted heating boilers are equipped with an electronic control and monitoring board for equipment operation. This part is very sensitive to any kind of stress that can be caused by:

voltage drops in the network;
accumulation of static charge, which increases in thunderstorm weather;
incorrectly selected temperature mode of the optional settings.

So, for example, Junkers OW23AE double-circuit gas boilers sometimes, when switched on in heating or water heating mode, do not produce a spark on the burner. The reset buttons and indicators start flashing. This indicates a malfunction of the board and can lead to a short circuit and malfunction:

air duct fan;
differential pressure switch;
NTC sensors for direct hot water pipelines.

The layout of the board sensors for the Junkers Euroline series (used when detecting stuck contacts on the relay)

Repairing the board is very expensive and is carried out only by professionals, therefore, in the event of a failure, it is recommended to purchase a new electronic circuit in company stores, which, as a result, also costs a lot. Therefore, it is recommended to monitor the operation of the boiler and its sensors during the entire operation of the device:

timely clean the coolants;
monitor the grounding of the case;
install voltage stabilizers.

A common cause of malfunctions can be the contamination of the boiler furnace chamber and the presence of a large amount of soot in it, which may be associated with the poor quality of natural gas. The breakdown indicator is uneven heating of the coolant, incomplete combustion of the gas, the impossibility of heating the water above 45 degrees Celsius, since the coolant overheating sensor is triggered. Such a failure can be observed in the Junkers Ceraclass series.

Preventive maintenance to eliminate contamination includes the following stages of work:

All valves must be closed before starting work.

remove the front covers, disconnect the wire leading to the piezoelectric element;
relieve the pressure of the water in the boiler by turning on the water tap and letting the water drain into the sink;
check the gas pressure by connecting a pressure gauge to the gas valve fitting;
unscrew the thermocouple, ignition electrode, burner tube;
replace the old gasket under the pilot burner with a new one;
remove the nozzle and flue;
brush the swirlers, base and outside of the heat exchanger;
blow out the inside of the heat exchanger with a vacuum cleaner;
process the burner itself with a brush and a brush;
wipe the gas duct on all sides with a rag;
brush the outer part of the nozzle, and use a thin needle to clean the hole;
assemble the elements in the reverse order, trying not to confuse their locations and not to violate the integrity.

How to repair gas boilers of the Junkers Novatherm ZW20KE series, in which there is also a problem of water heating, can be found in the video below.

Junkers recommends repairs, cleaning and diagnostics to identify deviations in the operation of boilers in special centers. The official service guarantees the quality of the work carried out through the use of various preventive methods: hydrodynamic cleaning, washing stands using chemicals (usually sulfamic acid or gel for washing in a booster).Cleaning the heat exchanger with a booster

Video (click to play).

You can also clean copper or steel heat exchangers from plaque and scale with your own hands using 9% acetic and citric acid by boiling. It is permissible to use improvised means: metal scrapers or brushes. It is recommended to clean the boilers 1-2 times a year before the start of the heating season, and install filters on the water supply system so that the water does not leave salt deposits.